First record of the invasive alien mussel Mytella strigata (Hanley, 1843) in Hong Kong

Abstract

The brackish water mytilid mussel Mytella strigata (Hanley, 1843) is recorded for the first time in July 2022 in Hong Kong. Native to Central and South America, the first reports of M. strigata in Asia were recorded in the Philippines, with subsequent reports from India, Singapore, Thailand, and Taiwan. Here, the mussels were found attached to hard, artificial substrates throughout the Tolo and Victoria Harbours in Hong Kong, with 13 accessible specimens collected and more inaccessible specimens observed. Mytella strigata tended to co-occurr with a previously recognised introduced mussel, Xenostrobus securis (Lamarck, 1819). The largest individual observed had a shell length of ~ 54 mm and the smallest ~ 22 mm, and all specimens were found in brackish water areas. Externally, the shells were generally black with a green tinge and internal surfaces were iridescent purple. Two small teeth on the internal anteroventeral margin, typical of Mytella , were observed. With the recent introduction of M . strigata throughout Asia, future research is required to document the full extent of the population within Hong Kong, as well as developing a greater understanding of the ecological and economic impacts of this highly invasive species.